Glutamic Acid

Some important facts about Glutamic acid:
Glutamic acid is one of only two amino acids (the other being aspartic acid) that has a net negative charge at physiological pH because it has a carboxylic acid moiety on the side chain. This negative charge makes glutamic acid a very polar molecule and it is usually found on the outside of proteins and enzymes where it is free to interact with the aqueous intracellular surroundings. Glutamic acid is biosynthesized from a number of amino acids including ornithine and arginine.
When aminated, glutamic acid forms the important amino acid glutamine. On a molar basis, glutamic acid is incorporated into proteins at a rate of 6.2 percent compared to the other amino acids. Glutamic acid has one additional methylene group in its side chain than does aspartic acid. The side chain carboxyl of aspartic acid is referred to as the ß carboxyl group, while that of glutamic acid is referred to as the ? carboxyl group. The pKa of the ? carboxyl group for glutamic acid in a polypeptide is about 4.3, significantly higher than that of aspartic acid. This is due to the inductive effect of the additional methylene group.
In some proteins, due to a vitamin K dependent carboxylase, some glutamic acids will be dicarboxylic acids, referred to as ? carboxyglutamic acid, that form tight binding sites for calcium ion. Glutamic acid and a-ketoglutarate, an intermediate in the Krebs cycle, are interconvertible by transamination. Glutamic acid can therefore enter the Krebs cycle for energy metabolism, and be converted by the enzyme glutamine synthetase into glutamine, which is one of the key players in nitrogen metabolism. Also that glutamic acid is easily converted into proline. First, the ? carboxyl group is reduced to the aldehyde, yielding glutamate semialdehyde. The aldehyde then reacts with the a-amino group, eliminating water as it forms the Schiff base. In a second reduction step, the Schiff base is reduced, yielding proline.

Catabolism:
Glutaminase is an important kidney tubule enzyme involved in converting glutamine (from liver and from other tissue) to glutamate and NH3+, with the NH3+ being excreted in the urine. Glutaminase activity is present in many other tissues as well, although its activity is not nearly as prominent as in the kidney.
The glutamate produced from glutamine is converted to ketoglutarate, making glutamine a glucogenic amino acid. The catabolic path of the carbon skeletons involves simple 1-step aminotransferase reactions that directly produce net quantities of a TCA cycle intermediate. The glutamate dehydrogenase reaction operating in the direction of ketoglutarate production provides a second avenue leading from glutamate to gluconeogenesis.

Benefits of Glutamic acid:
Glutamine is converted to glutamic acid in the brain, which is essential for cerebral functions, and increases the amount of GABA (gamma-aminobutyric acid), which is required for brain functioning and mental activity. It is used in the muscles for the synthesis of muscle proteins, and is of use for the treatment of wasting muscles after illness or post-operative care.
Although the body requires nitrogen, free nitrogen in the body can be harmful since it forms ammonia - especially toxic to the brain. The liver normally converts ammonia to urea, excreted in the urine - but glutamic acid attaches itself to nitrogen and forms glutamic acid, while removing ammonia from the brain.It further is used in the body to balance the acid/alkaline level and is also the basis or building blocks of RNA and DNA. It serves as a source of fuel for cells lining the intestines and it is also used by white blood cells and is important for immune function. Glutamic acid is an important excitatory neurotransmitter, and glutamic acid is also important in the metabolism of sugars and fats. It helps with the transportation of potassium across the blood-brain barrier, although itself does not pass this barrier that easily.
It also shows promise in the future treatment of neurological conditions, ulcers, hypoglycemic come, muscular dystrophy, epilepsy, Parkinson's, and mental retardation.
Glutamic acid can be used as fuel in the brain, and can attach itself to nitrogen atoms in the process of forming glutamine, and this action also detoxifies the body of ammonia. This action is the only way in which the brain can be detoxified from ammonia. The fluid produced by the prostate gland also contains amounts of glutamic acid, and may play a role in the normal function of the prostate

Deficiency symptomsof glutamic acid:
Deficiency of this nutrient is rare, since it can be manufactured by the body but deficiencies can develop during periods of fasting, starvation, strict dieting, cirrhosis, and weight loss associated with AIDS and cancer.

Symptoms of high intake:
High dosages of glutamic acid may include symptoms such as headaches and neurological problems.

Daily requirement:
In the presence of good health, supplementation of glutamine should not be necessary.

Some other points:
If taking a tyrosine supplement it is best to take it at bedtime, or with a high carbohydrate meal to prevent competition of absorption with other amino acids. Folic acid, copper and vitamin B6 is a good combination to have with this nutrient to maximize absorption and effectiveness.

Sources of glutamic acid:
Food sources of glutamic acid include meat, poultry, fish, eggs, and dairy products, as well as some protein-rich plant foods. Glutamine is found in many high protein foods, such as fish, meat, beans, and dairy as well as in vegetables such as raw parsley and spinach.